Abstract

This document defines a tunneling protocol that can be encapsulated
in any other protocol. Using authentication tokens multiple tunnels
can be created from behind the same NAT. The tokens allow one to
identify the sender of the packet thus making it possible to
automatically switch over the endpoint. This protocol is intended as
an alternative to the proto-41 protocol in use for tunneling IPv6
over IPv4 packets over the internet. Due to the authentication this
protocol is especially useful for dynamic non-24/7 endnodes which are
located behind NATs and want to use for instance a IPv6 Tunnel
Broker. The protocol can carry any payload and thus is not limited to
only IPv6 over IPv4 but can also be used for IPv4 over IPv6 and many
other combinations of protocols.